1. Field of the Invention
The present invention relates to a method and apparatus for digitally transferring audio data and audio-related information.
2. Description of the Related Art
As used herein, xe2x80x9caudio dataxe2x80x9d is distinguished from xe2x80x9caudio-related informationxe2x80x9d. The xe2x80x9caudio dataxe2x80x9d is the information representing the actual sounds to be reproduced. The xe2x80x9caudio-related informationxe2x80x9d is defined as any information that does not directly represent the actual sounds to be reproduced, e.g., category codes, source numbers, and channel numbers.
Conventional methods for digitally transferring audio data and audio-related information are based on, for example, international standards such as IEC60958 and IEC61937.
IEC60958, which is used for transferring 2-channel linear PCM data, is used in a wide range of digital data transfer applications including CDs and DVDs. IEC61937 is used for the transfer of data other than linear PCM data, such as compressed data (e.g., data compressed according to the MPEG standards). In recent years, IEC61937 is used in applications where the multi-channel audio outputs from a DVD apparatus are utilized for reproduction by an external decoder amplifier connected to the DVD apparatus.
The aforementioned conventional methods for transferring audio data and audio-related information aim at simply reproducing the transferred audio data.
In recent years, frequencies such as 96 kHz, up to 192 kHz, are adopted as sampling frequencies for DVDs and the like.
However, the aforementioned conventional transfer standards do not support sampling frequencies such as 96 kHz and 192 kHz. Therefore, when a player is connected to an external apparatus, the original audio data is subjected to a down sampling process or the like for converting the sampling frequency to 48 kHz before transfer. In this case, however, there is a problem in that the external apparatus receiving the transferred data is not aware of the value of the sampling frequency at which the original audio data was sampled.
FIG. 5 shows an audio data transfer apparatus 100 as a consumer-use digital audio apparatus. The audio data transfer apparatus 100 includes an audio data transmitter 101 for transmitting audio data and an audio data receiver 102 for receiving the transmitted audio data, the transmitter 101 and the receiver 102 being interconnected via an audio data transfer interface 103 designed for audio data transfer.
Tables 1 and 2 show transfer conditions for transferring audio data from the audio data transmitter 101 in the aforementioned audio data transfer apparatus 100.
As shown in Table 1, the transfer conditions for the audio data transfer apparatus 100 include up-sampling, down-sampling, sampling conversion, N times speed transfer, 1/N times speed transfer, etc., in addition to transferring the original audio data at the originally-intended speed.
Under up-sampling, down-sampling, sampling conversion conditions, the sampling frequency of the transferred audio data differs from that of the original audio data. However, the audio-related information which is transferred In the conventional audio data transfer apparatus 100 does not include information concerning the sampling frequency of the original audio data. As a result, there is a problem in that the audio data receiver 102 cannot obtain any information concerning the sampling frequency of the original audio data.
Under conditions where audio data is transferred at an N times transfer speed or a 1/N times transfer speed, the sampling frequency of the original audio data is retained; however, the audio data receiver 102 cannot monitor the transferred data as it is (see Table 2). In order to properly monitor the audio data transferred under N times transfer or 1/N times transfer conditions, it is necessary to reproduce the audio data at an N times or 1/N times speed, or to reproduce the audio data at the sampling frequency of the original audio data while storing the transferred audio data in large memories. In the case of non-PCM data, subjecting the transferred data to a decoding process which does not involve some special measures would result in the audio information being reproduced with unwanted interruptions because the audio data receiver 102 often cannot perform the decoding process in time.
FIG. 6 illustrates an example of a conventional audio data/audio-related information recording format 300. As shown in FIG. 6, the conventional audio data/audio-related information recording format 300 contains no information indicating the sampling frequency of the original audio data or no information indicating the transfer speed of the transferred audio data. Hence, it is impossible for the audio data receiver 102 to detect the sampling frequency of the original audio data or the transfer speed of the transferred audio data.
According to one aspect of the present invention, there is provided a method for transferring audio data and audio-related information, comprising: a generation step of generating second audio data from first audio data; a transmission step of transmitting the second audio data and audio-related information associated with the second audio data; and a reception step of receiving the second audio data and the audio-related information, wherein the audio-related information includes information representing a sampling frequency of the first audio data.
In one embodiment of the invention, the transmission step comprises a conversion step of converting the sampling frequency of the first audio data into a sampling frequency which is suitable for reproduction at the reception step.
In another embodiment of the invention, the conversion step comprises a down-sampling.
In still another embodiment of the invention, the conversion step comprises an up-sampling.
In still another embodiment of the invention, the conversion step comprises a sampling conversion.
In still another embodiment of the invention, the reception step comprises displaying the sampling frequency of the first audio data on a display.
Alternatively, there is provided a method for transferring audio data and audio-related information, comprising: a transmission step of transmitting the audio data and audio-related information associated with the audio data; and a reception step of receiving the audio data and the audio-related information, wherein the audio-related information includes monitor information indicating whether or not the audio data is capable of being monitored in the reception step.
In one embodiment of the invention, the reception step comprises displaying the monitor information on a display.
In another embodiment of the invention, the method further comprises a muting step of muting the audio data if the monitor information indicates that the audio data is not capable of being monitored in the reception step.
Alternatively, there is provided a method for transferring audio data and audio-related information, comprising: a transmission step of transmitting the audio data and audio-related information associated with the audio data; and a reception stop of receiving the audio data and the audio-related information, wherein the audio-related information includes information representing a transfer speed of the audio data.
In one embodiment of the invention, the reception step comprises displaying the transfer speed on a display.
According to another aspect of the present invention, there is provided an audio data/audio-related information transfer apparatus for transferring audio data and audio-related information, comprising: a transmitter for transmitting second audio data and audio-related information associated with the second audio data, the second audio data being generated from first audio data; and a receiver for receiving the second audio data and the audio-related information, wherein the audio-related information includes information representing a sampling frequency of the first audio data.
In one embodiment of the invention, the transmitter converts the sampling frequency of the first audio data into a sampling frequency which is suitable for reproduction by the receiver.
In another embodiment of the invention, wherein the transmitter performs a down-sampling for the sampling frequency of the first audio data.
In still another embodiment of the invention, the transmitter performs an up-sampling for the sampling frequency of the first audio data.
In still another embodiment of the invention, the transmitter performs a sampling conversion for the sampling frequency of the first audio data.
In still another embodiment of the invention, the receiver comprises a display for displaying the sampling frequency of the first audio data.
Alternatively, there is provided an audio data/audio-related information transfer apparatus for transferring audio data and audio-related information, comprising: a transmitter for transmitting audio data and audio-related information associated with the audio data; and a receiver for receiving the audio data and the audio-related information, wherein the audio-related information includes monitor information indicating whether or not the audio data is capable of being monitored by the receiver.
In one embodiment of the invention, the receiver comprises a display for displaying the monitor information.
In another embodiment of the invention, the audio data is muted if the monitor information indicates that the audio data is not capable of being monitored by the receiver.
Alternatively, there is provided an audio data/audio-related information transfer apparatus for transferring audio data and audio-related information, comprising: a transmitter for transmitting audio data and audio-related information associated with the audio data; and a receiver for receiving the audio data and the audio-related information, wherein the audio-related information includes information representing a transfer speed of the audio data.
In one embodiment of the invention, the receiver comprises a display for displaying the transfer speed.
According to another aspect of the present invention, there is provided a transmitter for transmitting second audio data and audio-related information associated with the second audio data, the second audio data being generated from first audio data, wherein the audio-related information includes information representing a sampling frequency of the first audio data.
In one embodiment of the invention, the transmitter converts the sampling frequency of the first audio data into a sampling frequency which is suitable for reproduction by the receiver.
In another embodiment of the invention, the transmitter performs a down-sampling for the sampling frequency of the first audio data.
In still another embodiment of the invention, the transmitter performs an up-sampling for the sampling frequency of the first audio data.
In still another embodiment of the invention, the transmitter performs a sampling conversion for the sampling frequency of the first audio data.
According to another aspect of the present invention, there is provided a transmitter for transmitting audio data and audio-related information associated with the audio data, wherein the audio-related information includes monitor information indicating whether or not the audio data is capable of being monitored by the receiver.
Alternatively, there is provided a transmitter for transmitting audio data and audio-related information associated with the audio data, wherein the audio-related information includes information representing a transfer speed of the audio data.
According to another aspect of the present invention, there is provided a receiver for receiving second audio data and audio-related information associated with the second audio data, the second audio data being generated from first audio data and transmitted from a transmitter, wherein the audio-related information includes information representing a sampling frequency of the first audio data.
In one embodiment of the invention, the receiver comprises a display for displaying the sampling frequency of the first audio data.
Alternatively, there is provided a receiver for receiving audio data and audio-related information associated with the audio data, wherein the audio-related information includes monitor information Indicating whether or not the audio data is capable of being monitored by the receiver.
In one embodiment of the invention, the receiver comprises a display for displaying the monitor information.
In another embodiment of the invention, the audio data is muted if the monitor information indicates that the audio data is not capable of being monitored by the receiver.
Alternatively, there is provided a receiver for receiving audio data and audio-related information associated with the audio data, the audio data being transmitted from a transmitter, wherein the audio-related information includes information representing a sampling frequency of the first audio data.
In one embodiment of the invention, the receiver comprises a display for displaying the transfer speed.
Thus, the invention described herein makes possible the advantage of providing a method and apparatus for performing digital transfer of audio data which involves concurrently transferring information indicating a sampling frequency, monitoring ability, and a transfer speed of audio data, thereby enabling a mode of audio reproduction which is in accordance with the particular audio data that is being transferred.
This and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.